The objectives of this proposal are to characterize the cell population kinetics, cell surface and cell organelle properties and related morphological and cytochemical parameters of the Chang rat hepatoma system growing as a transplantable solid tumor, in the ascites form and in tissue culture during various stages of cell cycle; to determine the role played by the vasculature in the growth and development of solid tumors; and to describe the relationship between the vasculature and repopulation kinetics in the solid tumors following chemotherapy. The transplantable Chang rat hepatomas, originally established in our laboratory, will be used for the proposed studies. This proposal is designed to employ a team of specialized investigators to conduct a coordinated research project. Using the methodology of tissue culture, cell kinetics, ultrastructure, cytochemistry, these investigators will study the dividing and nondividing tumor cells grown in vitro and in vivo; the cell growth characteristics; drug treatment responses; role of vasculature and tumor angiogenesis factor; cell migration, ultrastructural and cytochemical properties of cell surface and cell organelles. Data from these experiments will increase our knowledge of basic cancer cell biology and will be useful in the design of treatment protocols for cancer chemotherapy.